Celebrities have long used ghostwriters for autobiographies and other acts of self-aggrandizement. Now they are letting them loose on social networking sites like Twitter

The rapper 50 Cent is among the legion of stars who have recently embraced Twitter as a way to reach fans who crave near-continuous access to his life and thoughts. On March 1, he shared this insight with the more than 200,000 people who follow him: “My ambition leads me through a tunnel that never ends.”

Those were 50 Cent’s words, but it was not exactly him tweeting. Rather, it was Chris Romero, known as Broadway, the director of the rapper’s Web empire who typed in those words after reading them in an interview.

“He doesn’t actually use Twitter,” Romero said of 50 Cent, whose real name is Curtis Jackson III, “but the energy of it is all him.”

In its short history, Twitter — a microblogging tool which uses 140-character bursts — has become an important marketing tool for celebrities, politicians and businesses, promising a level of intimacy never before approached online, as well as giving the public the ability to speak directly to people and institutions once comfortably on a pedestal.

But someone has to do all that writing, even if it each entry is barely a sentence long. In many cases, celebrities and their handlers have turned to outside writers — ghost Twitterers, if you will — who keep fans updated on the latest twists and turns, often in the star’s own voice.

Because Twitter is seen as an intimate link between celebrities and their fans, many performers are not willing to divulge the help they get putting their thoughts down in cyberspace. Britney Spears recently advertised for someone to, among other things, help create content for Twitter and Facebook.

Kanye West recently explained to New York magazine that he’s hired two people to update his blog. “It’s just like how a designer would work,” he said. It is not only celebrities who are forced to look to a team to produce real-time commentary on daily activities; US politicians like Representative Ron Paul have had staffers assigned to create Twitter posts and Facebook personas. Candidate Barack Obama, as well as President Obama, has a social-networking team to keep his Twitter feed tweeting.

The famous, of course, have long used ghostwriters for autobiographies and other acts of self-aggrandizement. But the idea of having someone else write continual updates of one’s daily life seems slightly absurd.

The basketball star Shaquille O’Neal, for example, is a prolific Twitterer on his account — The Real Shaq — where he shares personal news, jokes and occasional trash talking against opponents with nearly 430,000 followers.

“If I am going to speak, it will come from me,” he said, noting that the technology allows him to bypass the media to speak directly to the fans.

As for the temptation to rely on a team to supply his words, he said: “It’s 140 characters. It’s so few characters. If you need a ghost writer for that, I feel sorry for you.”

Athletes seem to be purists. Lance Armstrong, only hours after breaking his right collarbone, tweeted about it, using his left hand. Charlie Villanueva, a forward for the Milwaukee Bucks tweeted at half-time from the locker room on March 15 about how “I gotta step up.” (His coach, Scott Skiles, was not pleased with his diversion, but the Bucks did win.)

But for politicians like Paul, who sought the 2008 Republican presidential nomination, Twitter is an organizing tool rather than a glimpse behind the curtain. “During the presidential campaign,” said Jesse Benton, Paul’s campaign manager, “we assigned a staffer to each social network site. Each was used to generate the same message as a way to amplify the message and drive people back to our site.”